scholarly journals p21 Disrupts the interaction between cdk2 and the E2F-p130 complex.

1996 ◽  
Vol 16 (3) ◽  
pp. 737-744 ◽  
Author(s):  
P Shiyanov ◽  
S Bagchi ◽  
G Adami ◽  
J Kokontis ◽  
N Hay ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Cyclin Dependent Kinase ◽  
Related Protein ◽  
Sensitive Mutant ◽  
Cycle Progression ◽  
Cell Extracts ◽  
A Cell ◽  
Transcription Factor E2f

In nonproliferating or growth-arrested cells, the transcription factor E2F remains bound to the retinoblastoma-related protein p130. Accumulation of this E2F-p130 complex correlates with an arrest of the cell cycle progression. Progression through G1 phase is associated with a cyclin-dependent binding of the cyclin-dependent kinase cdk2 to the E2F-p130 complex. By fractionating mouse L-cell extracts, we have obtained a partially purified preparation of the E2F-p130 complex that also contains cdk2. Incubation of this complex with recombinant p21 results in a disruption of the interaction between cdk2 and the E2F-p130 complex in extracts of a cell line that expresses a temperature-sensitive mutant of p53. Incubation at the permissive temperature (32 degrees C) results in an induction of p21 synthesis. An increase in the level of p21 in these cells correlates with a loss of cdk2 from the cdk2-containing E2F-p130 complex. We also show that the expression of a reporter gene containing E2F sites in the promoter region is reduced by the coexpression of p21. Since p21 is believed to be a mediator of p53, we speculated that the p21-mediated disruption of the cdk2-containing E2F-p130 complex plays a role in the growth suppression function of p53.

scholarly journals The Saccharomyces cerevisiae SDA1 gene is required for actin cytoskeleton organization and cell cycle progression

2000 ◽  
Vol 113 (7) ◽  
pp. 1199-1211
Author(s):  
G. Buscemi ◽  
F. Saracino ◽  
D. Masnada ◽  
M.L. Carbone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Replication ◽  
Actin Cytoskeleton ◽  
Cell Cycle Progression ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Cycle Progression ◽  
Cytoskeleton Organization ◽  
Actin Cytoskeleton Organization

The organization of the actin cytoskeleton is essential for several cellular processes. Here we report the characterization of a Saccharomyces cerevisiae novel gene, SDA1, encoding a highly conserved protein, which is essential for cell viability and is localized in the nucleus. Depletion or inactivation of Sda1 cause cell cycle arrest in G(1) by blocking both budding and DNA replication, without loss of viability. Furthermore, sda1-1 temperature-sensitive mutant cells arrest at the non-permissive temperature mostly without detectable structures of polymerized actin, although a normal actin protein level is maintained, indicating that Sda1 is required for proper organization of the actin cytoskeleton. To our knowledge, this is the first mutation shown to cause such a phenotype. Recovery of Sda1 activity restores proper assembly of actin structures, as well as budding and DNA replication. Furthermore we show that direct actin perturbation, either in sda1-1 or in cdc28-13 cells released from G(1) block, prevents recovery of budding and DNA replication. We also show that the block in G(1) caused by loss of Sda1 function is independent of Swe1. Altogether our results suggest that disruption of F-actin structure can block cell cycle progression in G(1) and that Sda1 is involved in the control of the actin cytoskeleton.

scholarly journals Structure Activity Relationship of Xanthones for Inhibition of Cyclin Dependent Kinase 4 from Mangosteen (Garcinia Mangostana L.

2019 ◽  
Vol 4 (4) ◽  
pp. 38-45 ◽  
Author(s):  
Bhaskar Vemu ◽  
Mirielle C. Nauman ◽  
Jacob P. Veenstra ◽  
Jeremy J. Johnson
Keyword(s):  
Cell Cycle Progression ◽  
Cyclin Dependent Kinase ◽  
Garcinia Mangostana ◽  
Cycle Progression ◽  
Structure Activity ◽  
A Cell ◽  
Key Functional Groups ◽  
Relationship Of ◽  
Unique Chemical

The mangosteen fruit is a popular Southeast Asian fruit consumed for centuries. There have been a variety of xanthones isolated from the fruit, bark, roots and leaves with each having unique chemical and physical properties. Previously, the most abundant xanthone α-mangostin has been shown to inhibit CDK4. Herein we describe the role of selected xanthones from the mangosteen inhibiting CDK4. The evidence we provide here is that key functional groups are required to inhibit the CDK4 protein to prevent the phosphorylation of downstream targets critical to inhibiting uncontrolled cell cycle progression. To define the properties of xanthones for inhibiting CDK4 we utilized a cell free biochemical assay to identify inhibitors of CDK4. The following xanthones were used for the analysis: α-mangostin, β-mangostin, γ-mangostin, gartanin, 8-desoxygartanin, garcinone C and garcinone D, 9-hydroxycalabaxanthone, and 3-isomangostin These results further substantiate the unique pharmacological properties of individual xanthones and how a mixture of xanthones may be responsible for a multi-targeted effect in cell based pharmacology systems.

scholarly journals Identification of G1 kinase activity for cdk6, a novel cyclin D partner.

1994 ◽  
Vol 14 (3) ◽  
pp. 2077-2086 ◽  
Author(s):  
M Meyerson ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Suppressor Gene ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Retinoblastoma Tumor Suppressor ◽  
Cell Extracts ◽  
Retinoblastoma Tumor ◽  
Cycle Regulation

A family of vertebrate cdc2-related kinases has been identified, and these kinases are candidates for roles in cell cycle regulation. Here, we show that the human PLSTIRE gene product is a novel cyclin-dependent kinase, cdk6. The cdk6 kinase is associated with cyclins D1, D2, and D3 in lysates of human cells and is activated by coexpression with D-type cyclins in Sf9 insect cells. Furthermore, we demonstrate that endogenous cdk6 from human cell extracts is an active kinase which can phosphorylate pRB, the product of the retinoblastoma tumor suppressor gene. The activation of cdk6 kinase occurs during mid-G1 in phytohemagglutinin-stimulated T cells, well prior to the activation of cdk2 kinase. This timing suggests that cdk6, and by analogy its homolog cdk4, links growth factor stimulation with the onset of cell cycle progression.

Identification of G1 kinase activity for cdk6, a novel cyclin D partner

1994 ◽  
Vol 14 (3) ◽  
pp. 2077-2086
Author(s):  
M Meyerson ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Suppressor Gene ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Retinoblastoma Tumor Suppressor ◽  
Cell Extracts ◽  
Retinoblastoma Tumor ◽  
Cycle Regulation

A family of vertebrate cdc2-related kinases has been identified, and these kinases are candidates for roles in cell cycle regulation. Here, we show that the human PLSTIRE gene product is a novel cyclin-dependent kinase, cdk6. The cdk6 kinase is associated with cyclins D1, D2, and D3 in lysates of human cells and is activated by coexpression with D-type cyclins in Sf9 insect cells. Furthermore, we demonstrate that endogenous cdk6 from human cell extracts is an active kinase which can phosphorylate pRB, the product of the retinoblastoma tumor suppressor gene. The activation of cdk6 kinase occurs during mid-G1 in phytohemagglutinin-stimulated T cells, well prior to the activation of cdk2 kinase. This timing suggests that cdk6, and by analogy its homolog cdk4, links growth factor stimulation with the onset of cell cycle progression.

scholarly journals A Yeast taf17 Mutant Requires the Swi6 Transcriptional Activator for Viability and Shows Defects in Cell Cycle-Regulated Transcription

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1561-1576
Author(s):  
Neil Macpherson ◽  
Vivien Measday ◽  
Lynda Moore ◽  
Brenda Andrews
Keyword(s):  
Cell Cycle ◽  
Transcriptional Activation ◽  
Essential Gene ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Synthetic Lethal ◽  
Cycle Arrest ◽  
A Cell ◽  
Allelism Tests ◽  
Complementation Groups

Abstract In Saccharomyces cerevisiae, the Swi6 protein is a component of two transcription factors, SBF and MBF, that promote expression of a large group of genes in the late G1 phase of the cell cycle. Although SBF is required for cell viability, SWI6 is not an essential gene. We performed a synthetic lethal screen to identify genes required for viability in the absence of SWI6 and identified 10 complementation groups of swi6-dependent lethal mutants, designated SLM1 through SLM10. We were most interested in mutants showing a cell cycle arrest phenotype; both slm7-1 swi6Δ and slm8-1 swi6Δ double mutants accumulated as large, unbudded cells with increased 1N DNA content and showed a temperature-sensitive growth arrest in the presence of Swi6. Analysis of the transcript levels of cell cycle-regulated genes in slm7-1 SWI6 mutant strains at the permissive temperature revealed defects in regulation of a subset of cyclin-encoding genes. Complementation and allelism tests showed that SLM7 is allelic with the TAF17 gene, which encodes a histone-like component of the general transcription factor TFIID and the SAGA histone acetyltransferase complex. Sequencing showed that the slm7-1 allele of TAF17 is predicted to encode a version of Taf17 that is truncated within a highly conserved region. The cell cycle and transcriptional defects caused by taf17slm7-1 are consistent with the role of TAFIIs as modulators of transcriptional activation and may reflect a role for TAF17 in regulating activation by SBF and MBF.

scholarly journals Budding yeast relies on G1 cyclin specificity to couple cell cycle progression with morphogenetic development

2021 ◽  
Vol 7 (23) ◽  
pp. eabg0007
Author(s):  
Deniz Pirincci Ercan ◽  
Florine Chrétien ◽  
Probir Chakravarty ◽  
Helen R. Flynn ◽  
Ambrosius P. Snijders ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Budding Yeast ◽  
Quantitative Model ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Model Cell ◽  
Mitotic Cyclin ◽  
Substrate Phosphorylation ◽  
The Cost

Two models have been put forward for cyclin-dependent kinase (Cdk) control of the cell cycle. In the qualitative model, cell cycle events are ordered by distinct substrate specificities of successive cyclin waves. Alternatively, in the quantitative model, the gradual rise of Cdk activity from G1 phase to mitosis leads to ordered substrate phosphorylation at sequential thresholds. Here, we study the relative contributions of qualitative and quantitative Cdk control in Saccharomyces cerevisiae. All S phase and mitotic cyclins can be replaced by a single mitotic cyclin, albeit at the cost of reduced fitness. A single cyclin can also replace all G1 cyclins to support ordered cell cycle progression, fulfilling key predictions of the quantitative model. However, single-cyclin cells fail to polarize or grow buds and thus cannot survive. Our results suggest that budding yeast has become dependent on G1 cyclin specificity to couple cell cycle progression to essential morphogenetic events.

scholarly journals Tracking the Cartoon mouse phenotype: Hemopexin domain–dependent regulation of MT1-MMP pericellular collagenolytic activity

2018 ◽  
Vol 293 (21) ◽  
pp. 8113-8127 ◽  
Author(s):  
Moustafa Sakr ◽  
Xiao-Yan Li ◽  
Farideh Sabeh ◽  
Tamar Y. Feinberg ◽  
John J. G. Tesmer ◽  
...  
Keyword(s):  
Cell Surface ◽  
Critical Role ◽  
Collagenolytic Activity ◽  
Temperature Sensitive ◽  
Type I ◽  
Permissive Temperature ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Golgi Network ◽  
Hemopexin Domain

Following ENU mutagenesis, a phenodeviant line was generated, termed the “Cartoon mouse,” that exhibits profound defects in growth and development. Cartoon mice harbor a single S466P point mutation in the MT1-MMP hemopexin domain, a 200-amino acid segment that is thought to play a critical role in regulating MT1-MMP collagenolytic activity. Herein, we demonstrate that the MT1-MMPS466P mutation replicates the phenotypic status of Mt1-mmp–null animals as well as the functional characteristics of MT1-MMP−/− cells. However, rather than a loss-of-function mutation acquired as a consequence of defects in MT1-MMP proteolytic activity, the S466P substitution generates a misfolded, temperature-sensitive mutant that is abnormally retained in the endoplasmic reticulum (ER). By contrast, the WT hemopexin domain does not play a required role in regulating MT1-MMP trafficking, as a hemopexin domain-deletion mutant is successfully mobilized to the cell surface and displays nearly normal collagenolytic activity. Alternatively, when MT1-MMPS466P–expressing cells are cultured at a permissive temperature of 25 °C that depresses misfolding, the mutant successfully traffics from the ER to the trans-Golgi network (ER → trans-Golgi network), where it undergoes processing to its mature form, mobilizes to the cell surface, and expresses type I collagenolytic activity. Together, these analyses define the Cartoon mouse as an unexpected gain-of-abnormal function mutation, wherein the temperature-sensitive mutant phenocopies MT1-MMP−/− mice as a consequence of eliciting a specific ER → trans-Golgi network trafficking defect.

Cyclin specificity: how many wheels do you need on a unicycle?

2001 ◽  
Vol 114 (10) ◽  
pp. 1811-1820 ◽  
Author(s):  
M.E. Miller ◽  
F.R. Cross
Keyword(s):  
Cell Cycle ◽  
Subcellular Localization ◽  
Cell Cycle Progression ◽  
Eukaryotic Cell ◽  
Cyclin Dependent Kinase ◽  
Temporal Expression ◽  
Cycle Progression

Cyclin-dependent kinase (CDK) activity is essential for eukaryotic cell cycle events. Multiple cyclins activate CDKs in all eukaryotes, but it is unclear whether multiple cyclins are really required for cell cycle progression. It has been argued that cyclins may predominantly act as simple enzymatic activators of CDKs; in opposition to this idea, it has been argued that cyclins might target the activated CDK to particular substrates or inhibitors. Such targeting might occur through a combination of factors, including temporal expression, protein associations, and subcellular localization.

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